KENNEDY SPACE CENTER, FLA. - A third solid rocket booster (SRB) is lifted up the launch tower on Launch Complex 17-A, Cape Canaveral Air Force Station. They are three of nine SRBs that will be mated to the Delta rocket to launch Mars Exploration Rover 2. NASA?s twin Mars Exploration Rovers are designed to study the history of water on Mars. These robotic geologists are equipped with a robotic arm, a drilling tool, three spectrometers, and four pairs of cameras that allow them to have a human-like, 3D view of the terrain. Each rover could travel as far as 100 meters in one day to act as Mars scientists' eyes and hands, exploring an environment where humans can?t yet go. MER-2 is scheduled to launch June 5 as MER-A. MER-1 (MER-B) will launch June 25.